WITN: Collaborative research in Location Dependent Data Management

该研究项目由南卫理公会大学的Margaret Dunham （IIS-9979458）和堪萨斯城密苏里大学的Vijay Kumar （IIS-9979453）合作完成，并得到了无线信息技术和网络（WITN）计划（NSF 99-68）的支持。本研究的目标是在移动计算平台上开发处理与地理位置密切相关的数据的方案。与传统的数据处理系统不同，在无线移动计算环境中，数据的价值可能取决于位置，并且在一个站点处理事务的结果可能与在另一个站点处理事务的结果不同。这种情况确定了一种新的数据类型，我们称之为位置相关数据（Location Dependent data， LDD）。因此，LDD是一类数据，其值由(a)数据存储的地理位置和(b)查询发起的移动单元（MU）的地理位置决定。例如，当来自MU的查询想要查找有关当地酒店的信息时，它在达拉斯得到的答案与在堪萨斯城得到的答案不同。甚至有可能从达拉斯开车到堪萨斯城的旅行者在途中问同样的问题，但特别使用堪萨斯城的数据而不是基于他请求查询的位置的数据来请求回答。尽管可以以完全相同的方式声明查询，但它是在与位置相关的上下文中解释的。本研究的目的是进一步探讨LDD的概念，其对事务处理的影响，并制定有效的管理方案。作为这项研究的结果，将产生有助于在移动设备上存储位置相关数据的方法，以及有效处理访问此类数据的交易的技术。创建测试平台是该项目的主要目标。它将用于实施和比较研究期间提出的各种策略。

This research project is a collaborative effort of Margaret Dunham, Southern Methodist University (IIS-9979458) and Vijay Kumar, University of Missouri at Kansas City (IIS-9979453) and is supported under the Wireless Information Technology and Networks (WITN) initiative, NSF 99-68. The goal of this research is to develop schemes for processing data that are strongly related to geographical locations, on a mobile computing platform. Unlike conventional data processing systems, in a wireless mobile computing environment the value of data may depend on location, and processing of a transaction at one site may give different results than that at another. This situation identifies a new type of data, which we refer to as Location Dependent Data (LDD). Thus, LDD is a class of data whose value is determined by (a) the geographical location of data storage and (b) the geographical location of the Mobile Unit (MU) where the query originated. For example, when a query from a MU wants to find out information about local hotels, it will get a different answer in Dallas than in Kansas City. It would even be possible for a traveler driving from Dallas to Kansas City to ask the same question en route but specifically request the response using Kansas City data rather than data based on the location from which he requests the query. Although the query may be stated in exactly the same way, it is interpreted in a location-dependent context. The objective of this research is to further explore the concept of LDD, its impact on transaction processing, and develop efficient schemes for its management. As a result of this research, methods will be produced which facilitate the storage of location dependent data at Mobile Units and techniques to efficiently process transactions which access this type of data. The creation of a testbed to is a major objective of the project. It will be used to implement and compare the various strategies proposed during the research.